杂交三倍体泥鳅性腺发育观察及其基因表达分析

以杂交三倍体泥鳅(4n♀×2n♂)为研究对象,对其早期性腺分化的组织学进行观察,并采用荧光定量PCR(qRT-PCR)技术,对杂交三倍体泥鳅早期不同发育时期(孵化后4、14、21、23、50、60和65d)和不同组织(性腺、肝脏、肌肉、肠、鳃、鳍、皮肤和脑)中性腺发育相关基因(hormad1、dmrt1-a)的表达量进行定量检测。研究结果发现:在早期不同发育时期,hormad1和dmrt1-a基因均为在4日龄中表达量最高,14日龄次之,在50日龄中表达量最低。在不同组织中,hormad1基因在雌鱼的鳍中表达量最高,肝脏中表达量最低;在雄鱼的性脑腺中表达量最高,肝脏中表达量最低。dmrt1-a基因在雌雄鱼的性腺中表达量最高,脑中表达量最低。杂交三倍体泥鳅早期性腺的分化和发生与二倍体泥鳅无差别,可观察到原始生殖细胞、原始生殖细胞的迁移和原始性腺的生成及性腺的分化等过程。研究结果表明,hormad1、dmrt1-a这2个基因与杂交三倍体泥鳅早期性腺发育密切相关。     

水稻磷酸核酮糖激酶基因OsPRK克隆、亚细胞定位与诱导表达分析

为探究水稻磷酸核酮糖激酶基因OsPRK在水稻诱导抗虫反应中的功能,以水稻秀水110为材料克隆OsPRK基因的全长,通过生物信息学软件分析其序列特征,并应用实时荧光定量PCR技术分析OsPRK基因在水稻不同组织中的分布情况以及在虫害诱导、激素和机械损伤处理水稻中的表达特征。结果显示,水稻OsPRK基因序列全长为1 212 bp,编码403个氨基酸,分子量为44.86 kD,具有1个磷酸核酮糖激酶保守结构域。OsPRK蛋白亚细胞定位结果显示其定位于叶绿体。OsPRK基因在水稻中的表达具有组织特异性,其在内叶、外叶、内叶鞘、外叶鞘和根系这5个组织中相对于内参基因ACTIN的表达量分别为35.83、20.53、6.25、3.21和0.03。与对照相比,二化螟Chilo suppressalis为害能够强烈抑制水稻茎秆中OsPRK基因的表达;褐飞虱Nilaparvata lugens怀卵雌成虫为害1.5、24 h、白背飞虱Sogatella furcifera怀卵雌成虫为害1、8、24 h以及机械损伤处理3、6、24 h均能显著诱导水稻茎秆中OsPRK基因的表达;而OsPRK基因的表达量在茉莉酸处理6、12 h时以及水杨酸处理0.5、1.5 h时被显著抑制,在茉莉酸处理48 h和水杨酸处理24 h时被显著诱导。表明OsPRK基因可能参与了水稻对害虫的诱导防御反应。     

嗜水气单胞菌J-1株OmpA融合蛋白的高效表达及免疫原性分析

以嗜水气单胞菌（Aeromonas hydrophila）J-1株基因组为模板，根据GenBank已发表的嗜水气单胞菌外膜蛋白的基因序列设计1对引物，扩增去除信号肽序列的成熟外膜蛋白OmpA的基因片段，定向克隆至表达质粒pET32a（＋）中，重组质粒经限制性酶切鉴定后测序。结果表明，插入片段长度为948bp，与NCBI上登录的几个相关序列相比，同源性在93．1％-95％之间，缺失4个氨基酸。将重组原核表达质粒pET32a-OmpA转化至大肠杆菌BL21（DE3），经诱导可表达分子量约57．4kD的蛋白，凝胶薄层扫描显示OmpA在转化菌中表达量占全菌蛋白的50％以上。用兔抗J-1株总外膜蛋白血清进行Western blot，在57．4kD处有明显反应条带。融合蛋白经Ni-NTA树脂柱亲和层析纯化后免疫新西兰兔制备抗血清，ELISA效价达1：12800以上。Western blot检测结果显示，该血清与9株具有代表性的气单胞菌的分子量约35kD的外膜蛋白均有较强反应，说明所表达的融合蛋白不仅保持原有外膜蛋白的免疫原性，而且提示OmpA可能是嗜水气单胞菌的共同保护性抗原。[中国水产科学，2008，15（2）：301—306]     

文学符号的蕴藉

文学总是以话语蕴藉的形态而存在，无论是作者还是读者，都只能通过这种话语蕴藉而参与到文学活动中。符号学理论认为，文学语言是具有审美功能的语言，美学功能不以传达了什么为中心，而以如何传达为中心。笔者拟从传达美学的角度分析文学符号的蕴藉。     

哺乳动物SRY基因研究进展

尽管SRY基因的发现已有10多年，但到目前为止，人们还没有弄清楚SRY基因是如何调控胚胎双性腺发育成睾丸的。经过10多年的研究，人们对SRY基因有了新的认识。作者综述了SRY基因的功能，SRY蛋白以及SRY基因在性腺中表达的最新研究进展。     

拟态弧菌外膜蛋白OmpU 基因的原核表达及其免疫保护性研究

自行构建的pMD18T-OmpU重组克隆质粒经BamHI/EcoRI双酶切后,定向插入原核表达质粒pGEX-4T-1中构建重组表达质粒pGEx-4T-1-OmpU.将重组表达质粒转化至大肠杆菌E.coli BL21进行IPTG诱导表达.表达产物经SDS-PAGE电泳及Western-blot分析显示,以包涵体形式表达的GST-OmpU融合蛋白的分子量约为62.9 kD,可与鼠抗拟态弧菌外膜蛋白(Omps)免疫血清发生特异性反应,提示重组OmpU保留了天然Omps的抗原性.用纯化的融合蛋白免疫昆明系小鼠,以50LD50拟态弧菌(5×103CFU/mL)攻击,小鼠的免疫保护率为60%(9/15).表明OmpU是拟态.弧菌的保护性抗原之一,具有研发成为外膜蛋白基因工程亚单位苗的潜在价值.     

Spatial distribution patterns and environmental interpretation of Anthriscus sylvestris clonal buds

Anthriscus sylvestris, a weed found both in Europe and China, is a kind of representative clustered clonal plant and is a foe on dams and banks. It has been widely investigated in Europe for its powerful progenitive ability and tolerance to severely adverse environments. Our aims were to investigate and quantify its spatial distribution patterns in four types of community habitats, using a clustering method and adjacency lattice established by Greig-Smith. We concluded our environmental interpretation based on canonical correspondence analysis (CCA) appended to a Monte Carlo test with randomized seeding. The results indicate that the buds around the parent roots are in an aggregation distribution pattern in all scales (0.002–5.12 m²), but theoretical distribution fitting, like negative binomial and Poisson distribution, show that some sizes of several sampling locations are out of place. For this, spatial ordination gives a satisfactory answer implying the effect of environmental variables such as depth of humus layer, soil moisture, light condition, disturbance intensity and herb abundance. CCA accounts for 64.7% of the total environmental variation and the remaining variation may be counteracted in those five variances or can be interpreted by other factors like accumulating temperature, annual rainfall and altitude in landscape scale. With the aid of temporal sequencing, the suppressed type II (monodominant) may be the former mode of suppressed type I (stable type), where invasion is done with the help of disturbance from both humans and nature. The abundance of A. sylvestris can add to our cognition in diversity resistance hypothesis and our hypothesis on disturbance before or upon immigration. __________ Translated from Journal of Zhejiang Forestry Science and Technology, 2007, 27(3): 1–7, 11 [译自: 浙江林业科技]     

双向进水流道流态改善研究

结合上海外高桥造船基地 1 #、2 #船坞共用的双向进水船坞泵站模型试验 ,研究了双向进水泵站进水系统的水力特性 ,分析了双向进水泵站吸水室中产生回流及涡带的原因及其危害 ,提出了双向进水流道流态的改善措施     

Population Studies of Limonium stocksii (Plumbaginacea) from a Salt Desert Near the Arabian Sea Coast

Abstract

A population of Limonium stocksii was studied for one year at the upper end of Manora Creek along the Arabian Sea coast, near Karachi, Pakistan. The community was divided into three zones. Soil pH varied from 8.1 to 8.5. Soil conductivity was highest (191 dS m^?1) in September and lowest (55 dS m^?1) in June. Soil water content was relatively low and varied from 1.6% in February to 9.5% in June. Limonium stocksii maintained a persistent seed bank, which peaked at 5,887 seeds m^?2 in May. Very slow growth was observed; however, plants in the intermediate zone showed better growth than the other two zones. Stem and leaf tissue water content were affected by salinity fluctuations, but root tissue water remained unaffected. Sodium (Na⁺) and chloride (Cl^?) accumulated in stems and leaves more than other ions. Leaves also accumulated a very high amount of magnesium (Mg⁺⁺) compared to roots and stems.     

Soil Potassium Indices and Clay‐Sized Particles affecting Banana‐Wilt Expression Caused by Soil Fungus in Banana Plantation Development on Transported Volcanic Soils

Abstract

Relations among the expression of banana disease symptoms caused by the soil fungus Fusarium oxysporum f. sp. cubense, soil potassium (K)–sodium (Na) properties [soluble K‐Na ratios (SK/SS), potential buffering capacity for K (KBC), potassium adsorption ratio (KAR)], and clay‐sized particles were evaluated in Sorribas plots from the Canary Islands. Soils were sampled in areas of Sorribas where banana plants show positive or negative wilting symptoms characteristic of Panama disease. The Bartoli method was used for soil dispersion (Na resin). This method was able to show a clear separation between diseased and disease‐free areas by the amount of clay‐sized particles. Results also show that the greatest SK/SS ratios and clay‐sized particles in soils from diseased areas could explain the increase of water‐stable aggregate mass in these soils and the release of available iron (Fe) to soil solution in diseased areas, at least in Sorribas cultivated soils under the arid climate conditions of the Canary Islands.